Drying kinetics of fresh and osmotically pre-treated papaya (Carica papaya L.)

The aim of this work was to study and to model the drying kinetics of fresh and osmotically pre-treated papaya cubes (Carica papaya L.) using the diffusional model (Fick's second law) adapted to a cubic geometry, and an empirical two parameters model. The osmotic pre-treatment was carried out in an incubator at constant temperature and agitation. The drying process was carried out in a fixed bed dryer at two different temperatures and air velocities. At the beginning of the drying process of fresh papaya, drying rate was influenced by both air velocity and air temperature. But lose to the equilibrium condition, the drying rate was affected only by the air temperature. The physico-chemical changes in the papaya cubes during osmotic pre-treatment caused differences in the drying rate in the subsequent air drying process when compared to fresh papaya cubes. The effective diffusivities of water, calculated by diffusional model, were of the order of 10(-9) m(2)/S. (C) 2003 Elsevier Science Ltd. All rights reserved.